Energy conditions in a modified Brans-Dicke theory

TL;DR

This paper explores energy conditions in a modified Brans-Dicke theory derived from a 5D vacuum model, analyzing how these conditions are satisfied or violated in a universe modeled as a generalized anisotropic Bianchi type I spacetime.

Contribution

It introduces a modified Brans-Dicke theory using the induced matter approach from 5D vacuum, analyzing energy conditions in an anisotropic universe model.

Findings

Energy conditions can be satisfied or violated depending on model parameters.

The model provides insights into the large-scale behavior of an anisotropic universe.

Potential for realistic cosmological modeling in the current universe era.

Abstract

We consider a modified version of Brans-Dicke theory (MBDT) in four dimensions obtained by applying the induced matter method of Wesson to a 5D generalized Brans-Dicke theory. In 5D the model consists of pure vacuum, with no self-interacting potential, except for a scalar field. Constraining the 5D geometry to be a generalization of the anisotropic Bianchi type I universe model first studied by Kasner, we derive the induced energy-momentum. We discuss the energy conditions and their bounds in the MBDT with such an induced imperfect fluid, with an eye toward a realistic model of the present-day universe, and consider the large-scale behavior of that spatially homogeneous and anisotropic model. We discuss how the energy conditions would be satisfied or violated in the context of MBDT, with the aim of providing a feasible description of the universe in the current era.